数字用户线路信道模拟仿真系统设计与实现

发布时间：2018-05-26 17:24

本文选题：数字用户线路 + 串音干扰　；参考：《电子科技大学》2017年硕士论文

【摘要】：近几年光纤通信网络发展迅速,使得数字接入网在国内呈现“光进铜退”的趋势。然而,铜质双绞线的资源分布在国内外十分广泛,且造价成本低廉,因此以双绞线为介质的数字用户线路(DSL)技术仍具有很大的推广价值。新一代数字用户线路技术G.fast突破了原有30MHz带宽的限制,带宽达到百兆以上,真正能够在传输速率和网络带宽上与光纤网络相匹敌。因此,对数字用户线路设备(包括局端和用户端设备)的信道模拟测试工作就显得十分重要。对DSL设备的测试方式目前主要分为两种,一种是通过专用仪器,如信号发生器和频谱测量仪得到双绞线的传输特性,这种方式的主要缺点在于仪器的成本过高。另一种是基于实际传输线缆,通过铺设双绞线来对DSL信道传输特性进行测量,这种方式的主要缺点在于耗费大量的人力、物力、财力,且对工程现场有较高要求。正是基于此,项目组开发的xDSL信道模拟器具有重要意义,可以对多对线缆进行实时传输模拟,并最终通过了华为公司的验收工作。本文基于数字用户线路信道传输理论(主要包括传输线理论、信道模型与噪声模型等),在Simulink中实现了信道模拟仿真系统,用于对信道的传输特性进行模拟,并为xDSL信道模拟器的实现奠定了前期的理论基础。全文主要工作如下:首先对模拟仿真系统的整体需求进行了分析,确定了系统的整体结构和相关参数。信道与噪声的各种相应模型在标准中进行了简单定义,本文对信道与噪声模块的模拟仿真方法进行了详细的分析和设计,最终完成了整个数字用户线路信道模拟仿真系统的设计工作。完成系统设计后,本文在Simulink中进行了模拟仿真系统的实现。在分析了相关信道参数后,对信道和噪声的模拟模块仿真进行了实现,并与理论值进行对比,验证了系统实现的正确性。最后实现了信道仿真控制显示平台软件,用于对信道传输特性进行显示。最后是对整个系统的测试工作。本文分析了相应的测试方案,在此基础上分别对远端衰减模块、远端串扰模块以及整体系统进行了测试,验证了信道模拟仿真系统的正确性。最后是在硬件系统的相关测试,xDSL模拟器最终能达到所需要的性能,从而进一步证明了模拟仿真系统的正确性。
[Abstract]:With the rapid development of optical fiber communication network in recent years, the digital access network has shown the trend of "optical advance and retreat" in China. However, the resources of copper twisted-pair wires are widely distributed at home and abroad, and the cost is low. Therefore, the digital subscriber line (DSLs) technology with twisted pair wire as the medium still has great value of popularization. The new generation of digital subscriber line technology (G.fast) has broken through the limit of the original 30MHz bandwidth, and the bandwidth has reached more than 100 megabytes, which can really rival the optical fiber network in the transmission rate and network bandwidth. Therefore, it is very important to test the channel simulation of digital subscriber line equipment (including local and client devices). At present, there are two kinds of testing methods for DSL equipment, one is to obtain the transmission characteristics of twisted-pair wire through special instruments, such as signal generator and spectrum measuring instrument. The main shortcoming of this method is that the cost of the instrument is too high. The other is to measure the transmission characteristics of DSL channel by laying twisted-pair cable based on the actual transmission cable. The main disadvantage of this method is that it consumes a lot of manpower, material and financial resources, and has high requirements on the engineering site. Based on this, the xDSL channel simulator developed by the project team is of great significance. It can simulate the transmission of multiple cables in real time, and finally pass the acceptance work of Huawei Company. Based on the theory of digital subscriber line channel transmission (including transmission line theory, channel model and noise model, etc.), a channel simulation system is implemented in Simulink, which is used to simulate the transmission characteristics of the channel. It also lays a theoretical foundation for the realization of xDSL channel simulator. The main work of this paper is as follows: firstly, the overall requirements of the simulation system are analyzed, and the overall structure and related parameters of the system are determined. The corresponding models of channel and noise are defined simply in the standard. The simulation method of channel and noise module is analyzed and designed in detail in this paper. Finally, the design of the digital subscriber line channel simulation system is completed. After the system design is finished, the simulation system is implemented in Simulink. After analyzing the relevant channel parameters, the simulation of the channel and noise simulation module is implemented, and compared with the theoretical values, the correctness of the system is verified. Finally, the software of channel simulation control and display platform is implemented, which is used to display the channel transmission characteristics. Finally, the whole system is tested. Based on the analysis of the corresponding test schemes, the remote attenuation module, the remote crosstalk module and the whole system are tested, and the correctness of the channel simulation system is verified. Finally, the XDSL simulator can achieve the required performance in the hardware system test, which further proves the correctness of the simulation system.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TP391.9;TN915.6

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